Embodiments of the invention relate generally to power converters and more specifically to series resonant direct current (DC) to DC power converters.
DC to DC power converters are very prevalent in today's power systems. There are many applications of DC to DC converters, e.g., power supplies for cell phones, laptops, X-ray machines and telecommunications equipment. DC to DC converters are also used in hybrid electric vehicles or military/civil aircrafts and high voltage DC (HVDC) systems. Further, DC to DC converters may be used in photovoltaic systems for maximum power point tracking.
DC to DC converters are generally operated at a high switching frequency resulting in high switching losses. Further, in high power applications, the switching losses are even more significant because of high voltages and high currents involved therein. In one embodiment, resonant DC to DC converters are used to reduce the switching losses. Resonant converters employ switching of the converter devices at about zero voltage or zero current and thus, the switching losses are reduced. In one embodiment, resonant converters employ series capacitors to obtain the near zero voltage or zero current switching. These series capacitors in resonant converters need to handle high currents since they are in the main power flow path. Series capacitors rated for high ripple currents can be expensive and sizeable. In addition to this, the high ripple current combined with equivalent series resistances (ESR) of these capacitors result in high resistive (I2R) losses. Therefore, the efficiency and reliability of resonant power converters is affected.
Therefore, it is desirable to provide a system and a method that will address the foregoing issues.